The high-temperature β modification of iron(II) sulfate

Single crystals of the high-temperature modification of iron(II) sulfate, β-FeSO4, were grown using chemical transport reactions with HCl as transport agent. The title compound crystallizes in the CuSO4 structure (space group Pnma) and is isotypic with other divalent metal sulfates MIISO4 adopting this structure type (M = Mg, Co, Zn). The coordination polyhedron of the Fe2+ cation is a distorted octa­hedron (\overline{1} symmetry) with a [2+2+2] distribution of bond lengths. By edge-sharing of the [FeO6] octa­hedra, [FeO4/2O2/1]∞ chains are established parallel to [010]; these are linked into a framework by corner-sharing with slightly distorted SO4 tetra­hedra (m symmetry).